Power operated piston tool



Oct. 24, 1967 R. w. HENNlNG 3,348,751

POWER OPERATED P'IsToN TOOL A TTOR/VEV Oct. 24, 1967 R. WQHENNING POWER OPERATED PIsToN TOOL 3 Sheets-Sheet 2 Filed Aug. 2, 1965 INVENTOR. P05597 l/V HE/V/V/NG A TTORNEV Oct. 24, 1967 R. w. HENNING POWER OPERATED PISTON TOOL E Sheets-Sheet 5 Filed Aug. 2, 1965 JIJ INVENTOR. @055m nf. HMM/NG BY W e ATTORNEY United States Patent O 3,348,751 POWER OPERATED PISTON TOOL Robert W. Henning, North Haven, Conn., assignor to Olin Mathieson Chemical Corporation Filed Aug. 2, 1965, Ser. No. 476,367 7 Claims. (Cl. 227-8) ABSTRACT OF THE DISCLOSURE A power-actuated tool having a housing in which a barrel is mounted for movement between a breech open and a breech closed position. In the breech open position, the barrel, through a cocking mechanism, holds a firing pin in its cocked position with a spring rending to bias both the firing pin and barrel forwardly in the tool. A sleeve is provided about the forward end of the barrel having limited relative movement therewith. Stop means on the housing limits the rearward movement of the sleeve so that the barrel must be moved rearwardly in the tool relative to the tool until the muzzle ends of both the barrel and sleeve are substantially flush in order for the barrel to be in its breech closed position and the barrel cocked. In addition, a slot configuration may be provided in the housing so that the barrel must be rotated at one point during its rearward movement.

This invention relates generally to tools for driving fasteners into masonry, concrete, wood, steel or the like, and more particularly to a power-actuated tool utilizing a piston member.

Y In power-actuated tools of the above type, it is important from a safety standpoint that the tools can not be red unless properly positioned against a suitable surface. Moreover, it is highly desirable that such tools are so constructed that in the event the piston member is overdriven by virtue of the fastener being projected through the worksurface, there is no failure of any portion of the tool which could be propelled into free-flight.

It is therefore an object of this invention to provide a power tool which is incapable of being fired unless it is properly positioned against a suitable surface.

It is another object of this invention to provide a poweractuated -piston tool wherein piston failure due to overdriving of the piston is reduced.

It is a more specific object of this invention to provide a power-actuated piston tool so constructed that the piston member remains captive in the piston tool in the event of overdriving of the piston.

Yet another object of this invention is to provide means to buffer the piston member in the event of overdriving wherein the energy of the piston will be absorbed.

These, and other objects of the present invention, may be accomplished according to a preferred embodiment of this invention, by the provision of a piston member having a head portion and a ram portion mountedwithin a barrel member. The muzzle portion of the tool may include a fastener guide extending forwardly from the barrel member and a buffer housing secured to the muzzle end of the barrel and disposed about the fastener guide. A buffer member of polyurethane elastomeric material may be conned in all directions between the fastener guide and buffer housing. The internal surface of the fastener guide may include a tapered portion which is adapted to be engaged by a corresponding tapered portion on the shank portion of the piston in the event of overdrive of the piston whereby the energy of the piston is transmitted through the fastener guide to the buffer member.

An outer sleeve member may be disposed about the fastener guide and muzzle bushing. The barrel member is f-li f. ICC

capable of forward movement relative to the outer sleeve member and housing under the influence of a spring biased cocking rod, whereby the firing pin can not be actuated unless the tool is properly positioned against the work surface.

The invention may be more readily understood by reference to the following description of a preferred embodiment and the accompanying drawing in which:

FIGURE 1 is a transverse sectional view of a poweroperated tool constructed in accordance with the present invention and shown positioned against a suitable worksurface in the cocked position.

FIGURE 2 is a cross-sectional view taken along the lines 2 2 of FIGURE l.

FIGURE 3 is a cross-sectional vie-w taken along the lines 3 3 of FIGURE l.

FIGURE 4 is a transverse sectional view of the tool of FIGURE 1 showing the tool inclined with respect to the work surface.

FIGURE 5 is a transverse sectional View of the tool of FIGURE l showing the tool in its open position.

Referring more specifically to the drawing, FIGURE 1 shows a tool constructed in accordance with the present invention having a housing 2 including a tubular forward portion 4 and a rearward portion 6. The tubular forward portion 4 includes an elongated opening 7.

The rear-ward portion 6 houses the firing mechanism 8 and also includes ,a pistol grip 10 and trigger guard 12. The tiring mechanism S includes a breech block 14 having a frusto-conical opening 16 therein. A firing pin 18 is mounted behind the breech block and includes a frustoconical nose portion 20, a body portion 22 and a rearwardly extending rod portion 24. The tiring pin 18 is urged forwardly by a spring member 26. A detent member 28 extends radially downwardly from the body portion 22 of the firing pin. This detent member 28 may be spring biased outwardly by suitable spring means (not shown).

A cocking rod 30 is mounted for reciprocation in the rearward portion 6 of the housing 2 and has a forward portion 32 extending through the breech block 14 and into the tubular forward portion 4 of the housing. The cocking rod 30 may be spring biased forward by a suitable spring member 34. The cocking rod may also include an opening 35 through which the `detent member 28 on the ring pin 18 may extend. A trigger member 36 having a sear portion 38 may be pivotally mounted within the trigger guard 12 by pivot pin 40. The trigger is resiliently urged by spring member 42.

A barrel member 44 having a bore 46 is reciprocally mounted within the tubular portion 4 of the housing member 2. The 'breech end of the barrel member 44 includes a cartridge chamber 48 for receiving an explosive cartridge 50'. The barrel member 44 also includes an elonv gated Z-slot having ashort axially extending portion 52 adjacent the muzzle end of the barrel member 44, a circumferentially extending portion 54 and a relatively long, axially extending, portion 56 which extends from the circumferential portion 54 rearwardly to a point adjacent the breech end of the barrel. A screw member 58, threadedly attached to the forward portion 4 of the housing member 2, extends into the Z-slot to limit axial movenient and rotation of the barrel member 44 with respect to the housing 2.

A piston member 60 may be mounted for reciprocation within the bore 46 of the barrel member 44. The piston member 60 may include a cylindrical head portion 62 and a reduced elongated cylindrical shank portion 64. The shank portion 64 has a tapered portion 66 midway of its length. A piston ring 68 may be mounted Within a suitable groove 70 in the head portion 6-2.

A buffer housing 72 is attached to the muzzle end of the barrel by means of interlocking lugs 74 and 76 on the barrel member 44 and buffer housing 72 respectively. Relative rotation between the buffer housing 72 and the barrel member 44 may be prevented by means of a locking member 78.\In the preferred form of the invention, the locking member may comprise an elongated at member 80 having an upstanding flange portion 82. The locking member 78 is mounted in a recess 84 in the outer surface of the barrel member and is spring biased forwardly by a suitable spring member 86. The flange portion 82 is received in a suitable recess 87 in the rearward face of the buffer housing 72.

The buffer housing 72 may include a iirst cylindrical internal surface88 having a diameter greater than the diameter of the bore 46 of the barrel member 44, and a second cylindrical internal surface 90 having a diameter less than or equal to the bore 46 of barrel member 44. The two internal surfaces 88 and 90l are joined at a shoulder portion 92.

A fastener guide 94 having a longitudinally extending bore96 may be disposed within the buffer `housing72. The fastener guide 94 may include a cylindrical external surface 98 having a diameter substantially equal to the diameter of the second internal surface 90 in the buffer housing 72. The rearward end of the fastener guide 94 may include a circular iiange portion 99' having an external diameter equal to the internal diameter of the first internal surface 88 of the buffer housing 72. The flange portion 99 may also include `a flat circumferentially extending tapered surface 101 which abuts a similar surface 100 on the muzzle end of the barrel member 44. The bore 96 of the fastener `guide 80 may include a tapered portion 102 corresponding to the tapered portion 66 of the shank portion 64 of the piston member 60.

Disposed between the first internal surface 8S of the buffer housing 72 and the external surface 98 of the fastener guide 94 is a buffer member104. As can be seen particularly in FIGURES 1, 4 and 5, the buffer member 104 extends axially from the flange portion 96 of the fastener guide 94 to the shoulder 92 in the internal surface of the buffer housing 72. Thus, it can be seen that the buffer member 94 is confined in both the axial and radial directions.

The buffer member 104 comprises a hollow cylinderr of a polyurethane elastomer such as may be prepared by reacting an organic diisocyanate and a polyhydroxy compound in the presence of a suitable cross-linldng agent and curing the reaction product.

Suitable for use as the organic diisocyanate are mand p-phenylene di-isocyanate; toluene di-isocyanate, p,pdiphenyl di-isocyanate and substitution products thereof such as p,p-diphenyl3,3dimethyl (or -dimethoxy) diisocyanate; 1,5-naphthylene di-isocyanate; 4,4'diphenyl methane di-isocyanate; and tetra, penta, heXa-, hepta, and octamethylenew di-isoeyanate. Mixtures of di-isocyanates and tri-isocyanates as well as organic isothiocyanatesisuch as p,p'phenylene di-isothiocyanate may also be used.

Some of the suitable polyhydroxy compounds include polypropylene glycols, polybutylene glycols, other polyalkylene glycols fon-med from alkylene glycols having three or more carbon atoms and mixed polyglycols having at least percent of propylene oxide units of three or more carbon atoms which polyglycols are characterized by being linear and by having a molecular weight of atleast 600, aswell as condensation products of pentaerythritol and polyglycols preferably having less than 5 percent pentaerythritol and a molecular weight of at least 1000. Polymerized tetrahydrofuran may also be used.

Suitable cross-linking agents include the hydroxyl terminated polyesters such as methylene-bis-orthochloro aniline and other well-known cross-linking agents.

According to the preferred embodiment, the polyurethane elastomer material may be the cured reaction product of toluene di-isocyanate and polymerized tetrahydrofuran reacted in the presence of methylene-bis-orthochloronaniline.

A hollow cylindrical outer sleeve member 106 may be disposed about the fastener guide 94, buffer housing 72, and a part of the forward portion 4 of the housing member 2. As shown in the drawing, the sleeve member 106 includes a first cylindrical portion 108 having an internal diameter slightly greater than the external diameter of the fastener guide 94. A second cylindrical portion 110 may also be provided having a diameter substantially equal to the outer diameter of the buffer housing 72 and tubular forward portion 4 of the housing 2. A screw member 112 threadedly attached to the buffer housing 72 extends through an elongatedfslot 114 in the outer sleeve'member 106. The screw member 112 prohibits relative rotation of the sleeve member 106 with respect to the buffer housing 72 while permitting limited axial movement therewith.

The outer sleeve member 106 may also include a cutout portion 116 surrounding the head of the screw member 58 in the tubular forward portion 4 of the housing 2. The cutout portion 116 should 'be so configured that it permits some relative rotationof the outer sleeve member 106 with respect to the tubular portion 4 of the housing 2 and movement axially forward from the position shown in FIGURE 1.

In operation, a fastener member 118 is positioned in a counter bore 120` in the muzzle end of the fastener guide 94. The fastener member 118 may include an enlarged head portion 122 and a reduced shank portion 124. Aplastic tip or washer or other member 126 may be attached to the forward portion of the shank portion 124 and include a circular ange 128 adapted to center the fastener member 120 in the fastener guide 94.

After the forward end of the fastener guide 94 is posi tioned against a suitable work-surface 130, the operator must push forwardly on the pistol grip 10 such that the housing 2 moves forward relative to the fastener guide 94, and barrel member 44. As the tool is pushed forward, the end face 132 of the barrel member 44 contacts the end of the forward portion 32 of cocking rod 30 and moves the cocking rod 30 rearwardly with respect to the housing 2. Since the detent member 28 extends into the opening 35 in the cooking rod 30, the forward movement of the tool serves to move the firing pin 18 rearwardly against the bias of its associated spring member 26 into the position shown in FIGURE 1. The tool may then be fired by pressing trigger member 36 whereupon the sear portion 38 will release the detent member 28 from the slot in the cocking rod. The firing pin 18 then moves forward under the action of its spring member 26 and the nose portion 20vwill be projected through the frusto-conical opening 16 in the breech block 14 and strike the cartridge 50.

However, if, after the tool is positioned flush against the work surface 130, it is tilted to -a predetremined angle such as is shown in FIGURE 4, the cocking rod 30 will move the barrel member 44, and also the buffer housing 72, buffer member 104` and fastener guide 94 forward relative to the outer sleeve member 116 and housing 4.'In this position, even though the trigger member 36 is depressed, the tiring pin 18 will not be released since the sear portion 38 is no longer properly aligned to release the detent 28 from the cooking rod 30.

vAs another feature of this invention, if the operator grasps the outer sleeve member 106 and pushes it rear wardly with respect to the housing 2, such rearward movement is limited bythe edge 134 of the cutout 116 contacting the head of the screw member 58 in the tubular portion 4 of the housing 2. At this point, the buffer housing 72, fastener guide 94,butfer member 104 and barrel member 44 will have been moved rearwardly relative to the housing 2 only a portion of the required 75 distance to move the cocking -rOd 30 and firing pin 18 into proper alignment such that the sear portion 38 on the trigger member 36 is properly aligned with the detent 28 of the firing pin 18. Accordingly, the tool can not be tired unless positioned against a suitable surface.

After the tool is fired and 'the fastener 118 driven into place, the outer sleeve member 106 may be rotated to align the screw member 58 with the relatively long axially extending slot 56 in the barrel member 44. The outer sleeve member 106 may then be moved axially forward 4relative to the housing 2 carrying along with it the fastener guide 94, buffer housing 72, buffer member 104 and barrel member 44. As these components move forward, the piston member 60 is held stationary with respect to the housing 2 by abutment of the head portion 62 of the piston member 60 against the screw 58 which-extends into the bore 46 in the barrel member 44.,

At the end of such movement, the respective components of the tool will be positioned as shown in FIG- URE 5. The barrel member 44 will have moved forward to such an extent that the head portion 62 of the piston member 60 abuts the end 136 of the bore 46 in the barrel member 44. In addition, the elongated slot 7 in the forward portion 4 of the housing 2 permits access to the cartridge receiving chamber 48.

The spent cartridge may be ejected by suitable means and a new cartridge inserted in the cartridge receiving chamber 48. The outer sleeve member 106 may then be moved rearwardly toward the pistol grip of the tool until the screw member 58 abuts the forward end of the relatively long axially extending slot 56. The outer sleeve member 106 may then berotated such that the barrel member 44 is rotated relative to the housing 2 and the short axially extending slot 52 is aligned with the screw member 58, whereupon the tool is ready to be positioned against a suitable work surface for the next tiring operation.

In the event that the piston member 44 is overdriven, due to the fact that the fastener penetrated too deeply, or went through the work surface, the tapered portion 66 on its shank portion 64 will engage the tapered portion 102 in the bore 96 of the fastener guide 94. The energy of the piston member 44 will then be transmitted through the fastener guide 94 and be absorbed by the polyurethane elastomeric buffer member 104. In this regard, it is of particular significance that the buffer member 104 is completely confined in all directions between the buffer housing 72 and the fastener guide 94. By virtue of this arrangement, when the piston member 44 contacts the fastener guide 94 and tends to move it forward relative to the buffer housing 72, there can be no flow of the polyurethane elastomeric buffer member 104, and such member will absorb the excess energy of the piston with very little compression.

The use of polyurethane elastomeric material as the buffer member 104 provides several advantages not found in `tools heretofore constructed. It has been found that even with repeated overdriving of the piston, and consequently repeated usage of the buffer member, the polyurethane elastomeric material will not become permanently set and therefore, the polyurethane elastomeric buffer member will not have to be replaced after each such usage as in the case of conventional rubbers and other plastic materials.

The structural arrangement of the housing 2, barrel member 44, fastener guide 94, outer sleeve tube 106, and buffer housing 72 provides the advantage of preventing accidental air ring, as well as preventing accidental Ifiring due to dropping or slamming the barrel from the open to closed position. In addition, the abovedescribed structural arrangement will prevent the tool ifrom being fired if it is tilted beyond a predetermined angle with respect to the work surface.

While reference has been made above to a particular 6 embodiment of this invention, various alterations and modications will readily suggest themselves to those skilled in the art. Accordingly, the scope of this invention should be ascertained by reference to the following claims.

What is claimed is:

1. A power-actuated tool including a housing having a front and rear portion, barrel means having a breech end and a muzzle end slidably mounted in said front portion for movement between a forward breech open position and a rearward breech closed position, firing pin means slidably mounted in said rear portion, cooking means for moving said tiring pin means from a iired position to a cocked position as said barrel means is moved into its breech closed position, means biasing said firing pin means from said cocked position to said fire position, said biasing means operable through said cooking means to bias said barrel means forwardly from said breech closed position, sleeve means disposed about said barrel means adjacent the muzzle end thereof, said lsleeve means having limited relative axial movement with respect to said barrel means, means on said sleeve means for abutting said barrel means upon rearward movement of said sleeve means to move said barrel means toward its breech closed position against the bias of said tiring pin biasing means, means on said barrel means for abutment by said sleeve means upon forward movement thereof to move said barrel forwardly in the housing, stop means on said housing for limiting the rearward movement of said sleeve means to a position wherein said barrel means is spaced forwardly of its breech closed position, said cocking means and said tiring means being positioned in said tiring position upon movement of said barrel means rearwardly relative to said sleeve means into a position that said sleeve means is in abutment with said stop means and the muzzle end of said barrel means is flush with the muzzle end of said sleeve means.'

2. The power-actuated tool of claim 1 wherein said barrel means includes slot means, said slot means including a first axially extending portion, a second axially extending portion circumferentially spaced from said rst portion, and a circumferentially extending portion connecting the forward end of said irst portion with the rearward end of said second portion, and said front portion of said housing includes means secured thereto extending into said slot means to limit the movement of said barrel means within said housing to the path of said slot means.

3. A power-actuated tool including a housing having a front and rear portion, barrel means having a breech end and a muzzle end slidably mounted in said front portion for movement between a forward breech open position and a rearward breech closed position, tiring pin means slidably mounted in said rear portion, cooking means for moving said ring pin means from a red position to a cocked position as said barrel means is moved into its breech closed position, means biasing said tiring pin means toward its iired position, said biasing means also acting through said cooking means to bias said barrel means forwardly from said breech closed position, slot means in said barrel means including a first axially extending portion, a second axially extending portion circumferentially spaced from said irst portion, and a circumferentially extending portion connecting the forward end of said first portion and the rearward end of said second portion, means in said front part of said housing extending into said slot means to limit the movement of said barrel means to the path of said slot means, said rst portion of said slot extending from a point adjacent the breech end of said slot to a point where its forward end will be engaged by said means extending thereinto before said barrel is moved rearwardly into its breech closed position, and said second portion extending forwardly from said circumferentially extending portion a distance sufficient to permit the barrel to move rear- Wardly into its breech closed position before said means extending thereinto abuts the forward end thereof.

4. The power-actuated tool of claim 3 further including a bore in said barrel means, and piston means having an enlarged head portion slidably disposed in said bore, said means extending into said slot means extending through said slot means into said bore in a position to engage the head portion of said piston means.

5. The power-actuated tool of claim 2 further including a bore in said barrel means, and piston means having an enlarged head portion slidably disposed in said bore, said means secured to said housing extending through said slot means into said bore in a position to be engaged by the head portion of said piston means.

6. The power-actuated tool of claim 1 wherein said barrel means includes a barrel member, a hollow buffer housing detachably secured to the muzzle end of said barrel member, a guide member slidably disposed Within said fastener guide and extending from the muzzle end thereof, and buter means disposed between said buffer housing and said fastener guide, said sleeve means being disposed about said fastener guide and buffer housing.

7. The power-actuated tool of claim 6 wherein said butter housing and said barrel member are detachably secured by intersecting lug members on both the barrel member and buifer housing, said barrel member including a locking member biased toward said muzzle end and having an upstanding ange on one end thereof, and said buter housing including a recessed portion, said flange being positioned within said recessed portion.

References Cited UNITED STATES PATENTS 3,061,833 11/1962 De Care 227-10 3,172,119 3/1965 Siddons 227--10 XR ,3,283,983 11/1966 Neighorn et al. 227-11 GRANVILLE Y. CUSTER, JR., Primary Examiner. 

1. A POWER-ACTUATED TOOL INCLUDING A HOUSING HAVING A FRONT AND REAR PORTION, BARREL MEANS HAVING A BREECH END AND A MUZZLE END SLIDABLY MOUNTED IN SAID FRONT PORTION FOR MOVEMENT BETWEEN A FORWARD BREECH OPEN POSITION AND A REARWARD BREECH CLOSED POSITION, FIRING PIN MEANS SLIDABLY MOUNTED IN SAID REAR PORTION, COCKING MEANS FOR MOVING SAID FIRING MEANS FROM A FIRED POSITION TO A COCKED POSITION AS SAID BARREL MEANS IS MOVED INTO ITS BREECH CLOSED POSITION, MEANS BIASING SAID FIRING PIN MEANS FROM SAID COCKED POSITION TO SAID FIRE POSITION, SAID BIASING MEANS OPERABLE THROUGH SAID COCKING MEANS TO BIAS SAID BARREL MEANS FORWARDLY FROM SAID BREECH CLOSED POSITION, SLEEVE MEANS DISPOSED ABOUT SAID BARREL MEANS ADJACENT THE MUZZLE END THEREOF, SAID SLEEVE MEANS HAVING LIMITED RELATIVE AXIAL MOVEMENT WITH RESPECT TO SAID BARREL MEANS, MEANS ON SAID SLEEVE MEANS FOR ABUTTING SAID BARREL MEANS UPON REARWARD MOVEMENT OF SAID SLEEVE MEANS TO MOVE SAID BARREL MEANS TOWARD ITS BREECH CLOSED POSITION AGAINST THE BIAS OF SAID FIRING PIN BIASING MEANS, MEANS ON SAID BARREL MEANS FOR ABUTMENT BY SAID SLEEVE MEANS UPON FORWARD MOVEMENT THEREOF TO MOVE SAID BARREL FORWARDLY IN THE HOUSING, STOP MEANS ON SAID HOUSING FOR LIMITING THE REARWARD MOVEMENT OF SAID SLEEVE MEANS TO A POSITION WHEREIN SAID BARREL MEANS IS SPACED FORWARDLY OF ITS BREECH CLOSED POSITION, SAID COCKING MEANS AND SAID FIRING MEANS BEING POSITIONED IN SAID FIRING POSITION UPON MOVEMENT OF SAID BAREL MEANS REARWARDLY RELATIVE TO SAID SLEEVE MEANS INTO A POSITION THAT SAID SLEEVE MEANS IS IN ABUTMENT WITH SAID STOP MEANS AND THE MUZZLE END OF SAID BARREL MEANS IS FLUSH WITH THE MUZZLE END OF SAID SLEEVE MEANS. 